hgext/acl.py

match: add a subclass for dirstate normalizing of the matched patterns

This class is only needed on case insensitive filesystems, and only
for wdir context matches. It allows the user to not match the case of
the items in the filesystem- especially for naming directories, which
dirstate doesn't handle[1]. Making dirstate handle mismatched
directory cases is too expensive[2].

Since dirstate doesn't apply to committed csets, this is only created by
overriding basectx.match() in workingctx, and only on icasefs.  The default
arguments have been dropped, because the ctx must be passed to the matcher in
order to function.

For operations that can apply to both wdir and some other context, this ends up
normalizing the filename to the case as it exists in the filesystem, and using
that case for the lookup in the other context.  See the diff example in the
test.

Previously, given a directory with an inexact case:

  - add worked as expected

  - diff, forget and status would silently ignore the request

  - files would exit with 1

  - commit, revert and remove would fail (even when the commands leading up to
    them worked):

        $ hg ci -m "AbCDef" capsdir1/capsdir
        abort: CapsDir1/CapsDir: no match under directory!

        $ hg revert -r '.^' capsdir1/capsdir
        capsdir1\capsdir: no such file in rev 64dae27060b7

        $ hg remove capsdir1/capsdir
        not removing capsdir1\capsdir: no tracked files
        [1]

Globs are normalized, so that the -I and -X don't need to be specified with a
case match.  Without that, the second last remove (with -X) removes the files,
leaving nothing for the last remove.  However, specifying the files as
'glob:**.Txt' does not work.  Perhaps this requires 're.IGNORECASE'?

There are only a handful of places that create matchers directly, instead of
being routed through the context.match() method.  Some may benefit from changing
over to using ctx.match() as a factory function:

  revset.checkstatus()
  revset.contains()
  revset.filelog()
  revset._matchfiles()
  localrepository._loadfilter()
  ignore.ignore()
  fileset.subrepo()
  filemerge._picktool()
  overrides.addlargefiles()
  lfcommands.lfconvert()
  kwtemplate.__init__()
  eolfile.__init__()
  eolfile.checkrev()
  acl.buildmatch()

Currently, a toplevel subrepo can be named with an inexact case.  However, the
path auditor gets in the way of naming _anything_ in the subrepo if the top
level case doesn't match.  That is trickier to handle, because there's the user
provided case, the case in the filesystem, and the case stored in .hgsub.  This
can be fixed next cycle.

  --- a/tests/test-subrepo-deep-nested-change.t
  +++ b/tests/test-subrepo-deep-nested-change.t
  @@ -170,8 +170,15 @@
     R sub1/sub2/test.txt
     $ hg update -Cq
     $ touch sub1/sub2/folder/bar
  +#if icasefs
  +  $ hg addremove Sub1/sub2
  +  abort: path 'Sub1\sub2' is inside nested repo 'Sub1'
  +  [255]
  +  $ hg -q addremove sub1/sub2
  +#else
     $ hg addremove sub1/sub2
     adding sub1/sub2/folder/bar (glob)
  +#endif
     $ hg status -S
     A sub1/sub2/folder/bar
     ? foo/bar/abc

The narrowmatcher class may need to be tweaked when that is fixed.


[1] http://www.selenic.com/pipermail/mercurial-devel/2015-April/068183.html
[2] http://www.selenic.com/pipermail/mercurial-devel/2015-April/068191.html

# acl.py - changeset access control for mercurial
#
# Copyright 2006 Vadim Gelfer <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''hooks for controlling repository access

This hook makes it possible to allow or deny write access to given
branches and paths of a repository when receiving incoming changesets
via pretxnchangegroup and pretxncommit.

The authorization is matched based on the local user name on the
system where the hook runs, and not the committer of the original
changeset (since the latter is merely informative).

The acl hook is best used along with a restricted shell like hgsh,
preventing authenticating users from doing anything other than pushing
or pulling. The hook is not safe to use if users have interactive
shell access, as they can then disable the hook. Nor is it safe if
remote users share an account, because then there is no way to
distinguish them.

The order in which access checks are performed is:

1) Deny  list for branches (section ``acl.deny.branches``)
2) Allow list for branches (section ``acl.allow.branches``)
3) Deny  list for paths    (section ``acl.deny``)
4) Allow list for paths    (section ``acl.allow``)

The allow and deny sections take key-value pairs.

Branch-based Access Control
---------------------------

Use the ``acl.deny.branches`` and ``acl.allow.branches`` sections to
have branch-based access control. Keys in these sections can be
either:

- a branch name, or
- an asterisk, to match any branch;

The corresponding values can be either:

- a comma-separated list containing users and groups, or
- an asterisk, to match anyone;

You can add the "!" prefix to a user or group name to invert the sense
of the match.

Path-based Access Control
-------------------------

Use the ``acl.deny`` and ``acl.allow`` sections to have path-based
access control. Keys in these sections accept a subtree pattern (with
a glob syntax by default). The corresponding values follow the same
syntax as the other sections above.

Groups
------

Group names must be prefixed with an ``@`` symbol. Specifying a group
name has the same effect as specifying all the users in that group.

You can define group members in the ``acl.groups`` section.
If a group name is not defined there, and Mercurial is running under
a Unix-like system, the list of users will be taken from the OS.
Otherwise, an exception will be raised.

Example Configuration
---------------------

::

  [hooks]

  # Use this if you want to check access restrictions at commit time
  pretxncommit.acl = python:hgext.acl.hook

  # Use this if you want to check access restrictions for pull, push,
  # bundle and serve.
  pretxnchangegroup.acl = python:hgext.acl.hook

  [acl]
  # Allow or deny access for incoming changes only if their source is
  # listed here, let them pass otherwise. Source is "serve" for all
  # remote access (http or ssh), "push", "pull" or "bundle" when the
  # related commands are run locally.
  # Default: serve
  sources = serve

  [acl.deny.branches]

  # Everyone is denied to the frozen branch:
  frozen-branch = *

  # A bad user is denied on all branches:
  * = bad-user

  [acl.allow.branches]

  # A few users are allowed on branch-a:
  branch-a = user-1, user-2, user-3

  # Only one user is allowed on branch-b:
  branch-b = user-1

  # The super user is allowed on any branch:
  * = super-user

  # Everyone is allowed on branch-for-tests:
  branch-for-tests = *

  [acl.deny]
  # This list is checked first. If a match is found, acl.allow is not
  # checked. All users are granted access if acl.deny is not present.
  # Format for both lists: glob pattern = user, ..., @group, ...

  # To match everyone, use an asterisk for the user:
  # my/glob/pattern = *

  # user6 will not have write access to any file:
  ** = user6

  # Group "hg-denied" will not have write access to any file:
  ** = @hg-denied

  # Nobody will be able to change "DONT-TOUCH-THIS.txt", despite
  # everyone being able to change all other files. See below.
  src/main/resources/DONT-TOUCH-THIS.txt = *

  [acl.allow]
  # if acl.allow is not present, all users are allowed by default
  # empty acl.allow = no users allowed

  # User "doc_writer" has write access to any file under the "docs"
  # folder:
  docs/** = doc_writer

  # User "jack" and group "designers" have write access to any file
  # under the "images" folder:
  images/** = jack, @designers

  # Everyone (except for "user6" and "@hg-denied" - see acl.deny above)
  # will have write access to any file under the "resources" folder
  # (except for 1 file. See acl.deny):
  src/main/resources/** = *

  .hgtags = release_engineer

Examples using the "!" prefix
.............................

Suppose there's a branch that only a given user (or group) should be able to
push to, and you don't want to restrict access to any other branch that may
be created.

The "!" prefix allows you to prevent anyone except a given user or group to
push changesets in a given branch or path.

In the examples below, we will:
1) Deny access to branch "ring" to anyone but user "gollum"
2) Deny access to branch "lake" to anyone but members of the group "hobbit"
3) Deny access to a file to anyone but user "gollum"

::

  [acl.allow.branches]
  # Empty

  [acl.deny.branches]

  # 1) only 'gollum' can commit to branch 'ring';
  # 'gollum' and anyone else can still commit to any other branch.
  ring = !gollum

  # 2) only members of the group 'hobbit' can commit to branch 'lake';
  # 'hobbit' members and anyone else can still commit to any other branch.
  lake = !@hobbit

  # You can also deny access based on file paths:

  [acl.allow]
  # Empty

  [acl.deny]
  # 3) only 'gollum' can change the file below;
  # 'gollum' and anyone else can still change any other file.
  /misty/mountains/cave/ring = !gollum

'''

from mercurial.i18n import _
from mercurial import util, match
import getpass, urllib

testedwith = 'internal'

def _getusers(ui, group):

    # First, try to use group definition from section [acl.groups]
    hgrcusers = ui.configlist('acl.groups', group)
    if hgrcusers:
        return hgrcusers

    ui.debug('acl: "%s" not defined in [acl.groups]\n' % group)
    # If no users found in group definition, get users from OS-level group
    try:
        return util.groupmembers(group)
    except KeyError:
        raise util.Abort(_("group '%s' is undefined") % group)

def _usermatch(ui, user, usersorgroups):

    if usersorgroups == '*':
        return True

    for ug in usersorgroups.replace(',', ' ').split():

        if ug.startswith('!'):
            # Test for excluded user or group. Format:
            # if ug is a user  name: !username
            # if ug is a group name: !@groupname
            ug = ug[1:]
            if not ug.startswith('@') and user != ug \
                or ug.startswith('@') and user not in _getusers(ui, ug[1:]):
                return True

        # Test for user or group. Format:
        # if ug is a user  name: username
        # if ug is a group name: @groupname
        elif user == ug \
             or ug.startswith('@') and user in _getusers(ui, ug[1:]):
            return True

    return False

def buildmatch(ui, repo, user, key):
    '''return tuple of (match function, list enabled).'''
    if not ui.has_section(key):
        ui.debug('acl: %s not enabled\n' % key)
        return None

    pats = [pat for pat, users in ui.configitems(key)
            if _usermatch(ui, user, users)]
    ui.debug('acl: %s enabled, %d entries for user %s\n' %
             (key, len(pats), user))

    # Branch-based ACL
    if not repo:
        if pats:
            # If there's an asterisk (meaning "any branch"), always return True;
            # Otherwise, test if b is in pats
            if '*' in pats:
                return util.always
            return lambda b: b in pats
        return util.never

    # Path-based ACL
    if pats:
        return match.match(repo.root, '', pats)
    return util.never

def hook(ui, repo, hooktype, node=None, source=None, **kwargs):
    if hooktype not in ['pretxnchangegroup', 'pretxncommit']:
        raise util.Abort(_('config error - hook type "%s" cannot stop '
                           'incoming changesets nor commits') % hooktype)
    if (hooktype == 'pretxnchangegroup' and
        source not in ui.config('acl', 'sources', 'serve').split()):
        ui.debug('acl: changes have source "%s" - skipping\n' % source)
        return

    user = None
    if source == 'serve' and 'url' in kwargs:
        url = kwargs['url'].split(':')
        if url[0] == 'remote' and url[1].startswith('http'):
            user = urllib.unquote(url[3])

    if user is None:
        user = getpass.getuser()

    ui.debug('acl: checking access for user "%s"\n' % user)

    cfg = ui.config('acl', 'config')
    if cfg:
        ui.readconfig(cfg, sections=['acl.groups', 'acl.allow.branches',
            'acl.deny.branches', 'acl.allow', 'acl.deny'])

    allowbranches = buildmatch(ui, None, user, 'acl.allow.branches')
    denybranches = buildmatch(ui, None, user, 'acl.deny.branches')
    allow = buildmatch(ui, repo, user, 'acl.allow')
    deny = buildmatch(ui, repo, user, 'acl.deny')

    for rev in xrange(repo[node], len(repo)):
        ctx = repo[rev]
        branch = ctx.branch()
        if denybranches and denybranches(branch):
            raise util.Abort(_('acl: user "%s" denied on branch "%s"'
                               ' (changeset "%s")')
                               % (user, branch, ctx))
        if allowbranches and not allowbranches(branch):
            raise util.Abort(_('acl: user "%s" not allowed on branch "%s"'
                               ' (changeset "%s")')
                               % (user, branch, ctx))
        ui.debug('acl: branch access granted: "%s" on branch "%s"\n'
        % (ctx, branch))

        for f in ctx.files():
            if deny and deny(f):
                raise util.Abort(_('acl: user "%s" denied on "%s"'
                ' (changeset "%s")') % (user, f, ctx))
            if allow and not allow(f):
                raise util.Abort(_('acl: user "%s" not allowed on "%s"'
                ' (changeset "%s")') % (user, f, ctx))
        ui.debug('acl: path access granted: "%s"\n' % ctx)